Three critical NetScaler flaws; one exploit active, patch now

Three critical vulnerabilities in Citrix NetScaler ADC and NetScaler Gateway have been disclosed, including one that is actively being exploited in the wild. Citrix released fixes for three flaws, with the most severe, CVE20257775, described as a memory overflow that can enable remote code execution or a denial-of-service attack. The other two flaws, CVE20257776 and CVE20258424, could lead to unstable behavior or unauthorized access to management interfaces. Security teams have urged immediate upgrades to supported firmware branches, noting that no complete workarounds exist for these flaws.

CVE20257775 requires specific gateway configurations to be exploitable, such as NetScaler devices acting as VPN gateway, ICA proxy, CVPN, RDP proxy, or certain HTTP/SSL/QUIC services bound to IPv6. The vulnerability has a high severity rating and a reported ability for attackers to run arbitrary code remotely, potentially taking control of affected devices. CVE20257776, with a slightly lower, yet significant, impact, is linked to memory overflow that can trigger unpredictable behavior or a denial-of-service condition when a Gateway VPN setup includes a compatible profile. CVE20258424...